[enhancement]: Allow UserPrincipalName of (group) managed service accounts (gMSA)

[Darsstar]

Describe your feature request here

It would be nice to be able to use the UserPrincipalName of (group) managed service accounts during setup.

ComputerPrincipal.FindByIdentity(PrincipalContext, String) could perhaps be used in IsManagedServiceAccount to normalize to the SAMAccountName which is required for NetIsServiceAccount.
It would need to receive the unsanitized value. (NetIsServiceAccount seems to accept the $ just fine on the server I used to test, so a comment as to why that happens might be a good idea.)

Edit: https://serverfault.com/a/518290/408176 describes how we add a UPN to gMSA objects.